Abstract: The US trauma care system has been demonstrated to decrease injury related mortality and has been celebrated by the Institute of Medicine as a model for emergency care delivery. Unfortunately, about half of all injured patients and a third of severely injured patients are treated in hospitals outside of the trauma care system. A readily accessible means by which to better understand gaps in trauma care is needed to facilitate optimization of the trauma care system. The broad objective of the project proposed here is to create and evaluate a novel, interactive, web-based dissemination tool for trauma systems information in all 50 states and the District of Columbia. The specific aims of the proposed project are: (1) to create an interactive, web-based tool to disseminate information that accurately describes the "supply-side" of trauma care in the US including adult trauma centers, pediatric trauma centers, and nontrauma center hospital emergency departments, (2) to create an interactive, web-based tool to disseminate information that accurately describes the "demand-side" of trauma care in the US Including the local injury death burden and special populations such as children, older adults, and veterans, (3) to create an interactive, web-based tool to disseminate information that accurately measures geographic and population access to trauma care in the US and identifies areas of mismatch between the "supply" of trauma care resources and the "demand" for trauma care, and (4) to evaluate the usage and impact of this interactive, web-based dissemination tool for US trauma care systems planners from all 50 states and the District of Columbia. This study has the capacity to inform national trauma care planning, advance dissemination science, and demonstrate the use of a novel public health planning tool.